CALLENBACH; ERNEST. (2004). ECOLOGY - A POCKET GUIDE (REPRINT.). UNIVERSITIES PRESS.
Lua i Stíl Chicago (17ú heag.)CALLENBACH; ERNEST. ECOLOGY - A POCKET GUIDE. REPRINT. HYDERABAD: UNIVERSITIES PRESS, 2004.
Lua MLA (9ú heag.)CALLENBACH; ERNEST. ECOLOGY - A POCKET GUIDE. REPRINT. UNIVERSITIES PRESS, 2004.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.